24ABR
Baset Series Air Conditioners
Sizes 18 To 60
1 --- 1 / 2 To 5 N o m i na l To n s
Installation Instructions
TABLE OF CONTENTS
PAGE
SAFETY CONSIDERATIONS 2.......................
INSTALLATION RECOMMENDATIONS 2.............
INSTALLATION 3--10..............................
Step 1 -- Check Equipment & Jobsite 3...............
Step 2 -- Install on Solid Pad 3......................
Step 3 -- Clearance Requirements 3..................
Step 4 -- Operating Ambient 3......................
Step 5 -- Install TXV 3 -- 4.........................
Step 6 -- Make Piping Connections 4 -- 7..............
Step 7 -- Make Electrical Connections 7 -- 8............
Step 8 -- Compressor Crankcase Heater 8.............
Step 9 -- Install Electrical Accessories 8..............
Step 10 -- Start--Up 8 -- 9...........................
Step 11 -- Check Charge 10.........................
Step 12 -- Final Checks 10..........................
CARE AND MAINTENANCE 10......................
A05341
F i g . 1 --- 24ABR*
*Shown with dense coil guard option
NOTE: Read the entire instruction manual before starting the
installation.
SAFETY CONSIDERATIONS
Improper installation, adjustment, alteration, service,
maintenance, or use can cause explosion, fire, electrical shock, or
other conditions which may cause death, personal injury, or
property damage. Consult a qualified installer, service agency, or
your distributor or branch for information or assistance. The
qualified installer or agency must use factory-- authorized kits or
accessories when modifying this product. Refer to the individual
instructions packaged with the kits or accessories when installing.
Follow all safety codes. Wear safety glasses, protective clothing,
and work gloves. Use quenching cloth for brazing operations.
Have fire extinguisher available. Read these instructions
thoroughly and follow all warnings or cautions included in
literature and attached to the unit. Consult local building codes
and National Electrical Code (NEC) for special requirements.
Recognize safety information. This is the safety--alert symbol
When you see this symbol on the unit and in instructions or
manuals, be alert to the potential for personal injury. Understand
these signal words; DANGER, WARNING, and CAUTION.
24ABR
These words are used with the safety --alert symbol. DANGER
identifies the most serious hazards which will result in severe
personal injury or death. WARNING signifies hazards which
could result in personal injury or death. CAUTION is used to
identify unsafe practices which would result in minor personal
injury or product and property damage. NOTE is used to
highlight suggestions which will result in enhanced installation,
reliability, or operation.
!
WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Before installing, modifying, or servicing system, main
electrical disconnect switch must be in the OFF
position. There may be more than 1 disconnect switch.
Lock out and tag switch with a suitable warning label.
INSTALLATION RECOMMENDATIONS
NOTE: In some cases noise in the living area has been traced to
gas pulsations from improper installation of equipment.
1. Locate unit away from windows, patios, decks, etc. where
unit operation sound may disturb customer.
2. Ensure that vapor and liquid tube diameters are
appropriate for unit capacity.
3. Run refrigerant tubes as directly as possible by avoiding
unnecessary turns and bends.
4. Leave some slack between structure and unit to absorb
vibration.
5. When passing refrigerant tubes through the wall, seal
opening with RTV or other pliable silicon--based caulk.
(See Fig. 2.)
6. Avoid direct tubing contact with water pipes, duct work,
floor joists, wall studs, floors, and walls.
7. Do not suspend refrigerant tubing from joists and studs
with a rigid wire or strap which comes in direct contact
with tubing.(See Fig. 2.)
8. Ensure that tubing insulation is pliable and completely
surrounds vapor tube.
9. When necessary, use hanger straps which are 1 in. wide
and conform to shape of tubing insulation. (See Fig. 2.)
10. Isolate hanger straps from insulation by using metal
sleeves bent to conform to shape of insulation.
Avoid contact between tubing and structureNOTE:
OUTDOOR WALL INDOOR WALL
CAULK
INSULATION
THROUGH THE WALL
LIQUID TUBE
VAPOR TUBE
JOIST
HANGER STRAP
(AROUND VAPOR
TUBE ONLY)
1” MIN.
SUSPENSION
INSULATION
VAPOR TUBE
LIQUID TUBE
A94026
F i g . 2 --- Piping Installation
Outdoor unit contains system refrigerant charge for operation
with ARI rated indoor unit when connected by 15 ft. of
field--supplied or factory accessory tubing. For proper unit
operation, check refrigerant charge using charging information
located on control box cover and/or in the Check Charge section
of this instruction.
IMPORTANT: Maximum liquid--line size is 3/8--in. OD for all
residential applications including long line.
IMPORTANT: Always install the factory--supplied liquid--line
filter drier. If replacing the filter drier, refer to Product Data
Digest for appropriate part number. Obtain replacement filter
driers from your distributor or branch.
2
INSTALLATION
STEP 1 —Check Equipment and Job Site
UNPACK UNIT
Move to final location. Remove carton taking care not to damage
unit.
Equipment
Inspect
File claim with shipping company prior to installation if shipment
is damaged or incomplete. Locate unit rating plate on unit corner
panel. It contains information needed to properly install unit.
Check rating plate to be sure unit matches job specifications.
STEP 2 —Install on a Solid, Level Mounting Pad
If conditions or local codes require the unit be attached to pad, tie
down bolts should be used and fastened through knockouts
provided in unit base pan. Refer to unit mounting pattern in Fig.
3 to determine base pan size and knockout hole location.
For hurricane tie downs, contact local distributor for details and
PE (Professional Engineer) certification, if required by local
authorities.
On rooftop applications, mount on level platform or frame. Place
unit above a load--bearing wall and isolate unit and tubing set
from structure. Arrange supporting members to adequately
support unit and minimize transmission of vibration to building.
Consult local codes governing rooftop applications.
Roof mounted units exposed to winds may require wind baffles.
Consult the Application Guideline and Service Manual -Residential Split System Air Conditioners and Heat Pumps for
wind baffle construction.
NOTE: Unit must be level to within ±2_ (±3/8 in./ft.) per
compressor manufacturer specifications.
STEP 3 —Clearance Requirements
When installing, allow sufficient space for airflow clearance,
wiring, refrigerant piping, and service. Allow 30--in. clearance to
service end of unit and 48 in. above unit. For proper airflow, a
6--in. clearance on 1 side of unit and 12 in. on all remaining sides
must be maintained. Maintain a distance of 24 in. between units.
Position so water, snow, or ice from roof or eaves cannot fall
directly on unit.
3/8 ---in . Dia. Tiedown
Knockouts in Basepan
(2) Places
STEP 4 —Operating Ambient
The minimum outdoor operating ambient in cooling mode is
55_F, and the maximum outdoor operating ambient in cooling
mode is 125_F.
STEP 5 —Install TXV
NOTE: Applies to non--TXV and Puron TXV indoor units
only. If installing a rated and approved indoor coil without a
factory installed R--22 TXV, remove and replace the fixed orifice
or PuronR TXV expansion device with an R--22 TXV.
The thermostatic expansion valve is specifically designed to
operate with R--22. Do not use a PuronR TXV. An existing
PuronR TXV must be replaced with a factory--approved TXV
specifically designed for R--22. Refer to Product Data Sheet for
the appropriate TXV kit number.
!
UNIT OPERATION HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
All indoor coil units must be installed with a hard shut
off R-- 22 TXV metering device.
IMPORTANT: If not factory installed, the TXV should be
mounted as close to the indoor coil as possible and in a vertical,
upright position. Avoid mounting the inlet tube vertically down.
Valve is more susceptible to malfunction due to debris if inlet
tube is facing down. A factory--approved filter drier must be
installed in the liquid line.
Installing TXV in Place of
1. Pump system down to 2 psig and recover refrigerant.
2. Remove hex nut from piston body. Use backup wrench on
fan coils.
3. Remove and discard factory --installed piston. Be sure
Teflon seal is in place.
4. Reinstall hex nut. Finger tighten nut plus 1/2 turn.
NOTE: If the piston is not removed from the body, TXV will
not function properly.
CAUTION
Piston
24ABR24ABR
View From Top
UNIT BASE PAN
DIMENSIONS
26 X 26 9–1/8 4–7/16 21–1/4
31–1/2 X 31–1/2 9–1/8 6–9/16 24–11/16
35 X 35 9–1/8 6–9/16 28–7/16
F i g . 3 --- Tiedown Knockout Locations
On rooftop applications, locate unit at least 6 in. above roof
surface.
TIEDOWN KNOCKOUT LOCATIONS
A B C
A05177
!
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Use a brazing shield and wrap TXV with wet cloth or
use heat sink material.
5. Install TXV on indoor coil liquid line. Sweat swivel
adapter to inlet of indoor coil and attach to TXV outlet.
Use backup wrench to avoid damage to tubing or valve.
Sweat inlet of TXV, marked “IN” to liquid line. Avoid
excessive heat which could damage valve.
6. Install vapor elbow with equalizer adapter to suction tube
of line set and suction connection to indoor coil. Adapter
has a 1/4--in. male connector for attaching equalizer tube.
7. Connect equalizer tube of TXV to 1/4--in. equalizer fitting
on vapor line adapter.
8. Attach TXV bulb to horizontal section of suction line
using clamps provided. Insulate bulb with field--supplied
insulation tape. See Fig. 4 for correct positioning of
sensing bulb.
9. Proceed with remainder of unit installation.
3
CAUTION
10 O’CLOCK
2O’CLOCK
SENSING BULB
STEP 6 —Make Piping Connections
!
WARNING
STRAP
SUCTION TUBE
8O’CLOCK 4O’CLOCK
7/8
IN. OD & SMALLER
F i g . 4 --- Position of Sensing Bulb
Replacing TXV on Puron Indoor
1. Pump system down to 2 psig and recover refrigerant.
2. Remove coil access panel and fitting panel from front of
24ABR24ABR
cabinet.
3. Remove TXV support clamp using a 5/16--in. nut driver.
Save the clamp.
4. Remove Puron TXV using a backup wrench on flare
connections to prevent damage to tubing.
5. Using wire cutters, cut equalizer tube off flush with vapor
tube inside cabinet.
6. Remove bulb from vapor tube inside cabinet.
7. Braze equalizer stub--tube closed. Use protective barrier as
necessary to prevent damage to drain pan.
IMPORTANT: Route the equalizer tube of R--22 TXV through
suction line connection opening in fitting panel prior to replacing
fitting panel around tubing.
8. Install TXV with 3/8--in. copper tubing through small hole
in service panel. Use wrench and backup wrench, to avoid
damage to tubing or valve, to attach TXV to distributor.
9. Reinstall TXV support clamp (removed in item 3).
10. Attach TXV bulb to vapor tube inside cabinet, in same
location as original was when removed, using supplied
bulb clamps (nylon or copper). See Fig. 4 for correct
positioning of sensing bulb.
11. Route equalizer tube through suction connection opening
(large hole) in fitting panel and install fitting panel in
place.
12. Sweat inlet of TXV, marked “IN” to liquid line. Avoid
excessive heat which could damage valve.
13. Install vapor elbow with equalizer adapter to vapor line of
line set and vapor connection to indoor coil. Adapter has
a 1/4--in. male connector for attaching equalizer tube.
14. Connect equalizer tube of TXV to 1/4--in. equalizer fitting
on vapor line adapter. Use backup wrench to prevent
damage to equalizer fitting.
15. Proceed with remainder of unit installation.
LARGER THAN 7/8 IN. OD
Coil
A81032
PERSONAL INJURY AND ENVIRONMENTAL
HAZARD
Failure to follow this warning could result in personal
injury or death.
Relieve pressure and recover all refrigerant before
system repair or final unit disposal. Use all service
ports and open all flow--control devices, including
solenoid valves.
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
If ANY refrigerant tubing is buried, provide a 6--in. vertical
rise at service valve. Refrigerant tubing lengths up to 36--in.
may be buried without further special consideration. Do not
bury lines more than 36--in.
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
To prevent damage to unit or service valves, observe the
following:
S Use a brazing shield
S Wrap service valves with wet cloth or use a heat sink
material.
Outdoor units may be connected to indoor section using
accessory tubing package or field--supplied refrigerant grade
tubing of correct size and condition. Rated tubing diameters
shown in Table 1 are recommended up to 80 ft. See Product
Data for acceptable alternate vapor diameters and associated
capacity losses. For tubing requirements beyond 80 ft.,
substantial capacity and performance losses can occur. Following
the recommendations in the Longline Guideline will reduce these
losses. Refer to Table 1 for field tubing diameters. Refer to Table
2 for accessory requirements.
There are no buried--line applications greater than 36--in. allowed.
If refrigerant tubes or indoor coil are exposed to atmosphere, they
must be evacuated to 500 microns to eliminate contamination and
moisture in the system.
Outdoor Unit Connected to Factory Approved Indoor
Outdoor unit contains correct system refrigerant charge for
operation with factory approved ARI rated indoor unit when
connected by 15 ft. of field-- supplied or factory--accessory tubing,
and factory supplied filter drier. Check refrigerant charge for
maximum efficiency.
Refrigerant Tubing Connection
Connect vapor and liquid tubes to fittings on vapor and liquid
service valves (see Table 1.) Use refrigerant grade tubing
CAUTION
CAUTION
Unit
Outdoor
4
Connection
Sweat
!
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Service valves must be wrapped in a heat--sinking
material such as a wet cloth while brazing.
Table 1—Refrigerant Connections and Recommended Liquid and Vapor Tube Diameters (In.)
Use refrigeration grade tubing. Service valves are closed from
factory and ready for brazing. After wrapping service valve with
a wet cloth, braze sweat connections using industry accepted
methods and materials. Consult local code requirements.
Refrigerant tubing and indoor coil are now ready for leak testing.
This check should include all field and factory joints.
Diameter
RATED VAPOR
(up to 80 ft.*)
Tube
Diameter
UNIT SIZE
018, 024
030, 036
042, 048
060
Notes:
1. Tube diameters are for total equivalent lengths up to 80 ft..
2. Do not apply capillary tube or fixed orifice indoor coils to these units.
* For Tubing Set lengths between 80 and 200 ft. horizontal or 20 ft. vertical differential (250 ft.Total Equivalent Length), refer to the Longline Guide l in e --- A ir
Conditioners and Heat Pumps using R ---22
Connection
Diameter
3/8 3/8 5/8 5/8
3/8 3/8 3/4 3/4
3/8 3/8 7/8 7/8
3/8 3/8 7/8 1--1/8
LIQUID
Tube
Diameter
Connection
Table 2—Accessory Usage
REQUIRED FOR LOW ---AMBI-
Accessory
Crankcase Heater Yes Yes No
Evaporator Freeze Thermostat Yes
Winter Start Control Yes {
Accumulator No
Compressor Start Assist Capacitor
and Relay
Motor Master® Control
or
Low---ambient Pressure Switch
Support Feet Recommended
Liquid Line Solenoid Valve No
Ball Bearing Fan Motor Ye s}
* For Tubing Set lengths between 80 and 200 ft. horizontal or 20 ft. vertical differential (250 ft.Total Equivalent Length), refer to the Longline Guide l i n e --- A i r C o n -
ditionersandHeatPumpsusingR---22
}Required for low ---ambient controller (full modulation feature) and Motor Master control only.
{Only when low pressure switch is used.
ENT APPLICATIONS
(Below 55 °F)
Yes
Yes
REQUIRED FOR LONG LINE
APPLICATIONS* (Ov er 80 Ft.)
No
No
No
Yes
No
No
See Long --- Line Application
Guideline
No
REQUIRED FOR SEA
COAST APPLICATIONS
(Within 2 miles)
No
No
No
No
No
Recommended
No
No
24ABR
5
Install Liquid--Line Filter Drier
T
MICRONS
Indoor
Evacuate Refrigerant Tubing and Indoor
Coil
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Installation of filter drier in liquid line is required.
Refer to Fig. 5 and install filter drier as follows:
1. Braze 5--in. liquid tube to the indoor coil.
2. Wrap filter drier with damp cloth.
3. Braze filter drier to above 5 --in. liquid tube. Flow arrow
must point towards indoor coil.
4. Connect and braze liquid refrigerant tube to the filter drier.
CAUTION
24ABR
F i g . 5 --- Liquid Line Filter Drier
!
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Filter drier must be wrapped in a heat- --sinking material
such as a wet cloth while brazing.
A05178
!
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Never use the system compressor as a vacuum pump.
Refrigerant tubes and indoor coil should be evacuated
using the recommended deep vacuum method of 500
microns. The alternate triple evacuation method may be
used if the procedure outlined below is followed. Always
break a vacuum with dry nitrogen.
Deep Vacuum
The deep vacuum method requires a vacuum pump
capable of pulling a vacuum of 500 microns and a vacuum
gage capable of accurately measuring this vacuum depth.
The deep vacuum method is the most positive way of
assuring a system is free of air and liquid water. (See Fig. 6)
5000
4500
4000
3500
3000
2500
2000
1500
1000
500
Triple Evacuation
The triple evacuation method should only be used when
vacuum pump is only capable of pumping down to 28 in. of
mercury vacuum and system does not contain any liquid
water. Refer to Fig. 7 and proceed as follows:
1. Pump system down to 28 in. of mercury and allow
2. Close service valves and shut off vacuum pump.
3. Connect a nitrogen cylinder and regulator to system
4. Close ser vice valve and allow system to stand for 1 hr.
5. Repeat this procedure as indicated in Fig. 7. System
Method
LEAK IN
SYSTEM
VACUUM TIGH
TOO WET
TIGHT
DRY SYSTEM
01234567
MINUTES
F i g . 6 --- Deep Vacuum Graph
Method
pump to continue operating for an additional 15
minutes.
and open until system pressure is 2 psig.
During this time, dry nitrogen will be able to diffuse
throughout the system absorbing moisture.
will then be free of any contaminants and water vapor.
A95424
A95424
6
EVACUATE
BREAK VACUUM WITH DRY NITROGEN
WAIT
EVACUATE
BREAK VACUUM WITH DRY NITROGEN
WAIT
EVACUATE
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
The unit cabinet must have an uninterrupted or unbroken
ground to minimize personal injury if an electrical fault
should occur. The ground may consist of electrical wire or
metal conduit when installed in accordance with existing
electrical codes.
Connect Ground and Power Wir
Connect ground wire to ground connection in control box for
safety. Connect power wiring to contactor as shown in Fig. 8.
WARNING
es
CHECK FOR TIGHT, DRY SYSTEM
(IF IT HOLDS DEEP VACUUM)
CHARGE SYSTEM
A95425
F i g . 7 --- Triple Evacuation Method
Final Tubing
IMPORTANT: Check to be certain factory tubing on both
indoor and outdoor unit has not shifted during shipment. Ensure
tubes are not rubbing against each other or any sheet metal. Pay
close attention to feeder tubes, making sure wire ties on feeder
tubes are secure and tight.
STEP 7 —Make Electrical Connections
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Do not supply power to unit with compressor terminal
box cover removed.
Be sure field wiring complies with local and national fire, safety,
and electrical codes, and voltage to system is within limits shown
on unit rating plate. Contact local power company for correction
of improper voltage. See unit rating plate for recommended
circuit protection device.
NOTE: Operation of unit on improper line voltage constitutes
abuse and could affect unit reliability. See unit rating plate. Do
not install unit in system where voltage may fluctuate above or
below permissible limits.
NOTE: Use copper wire only between disconnect switch and
unit.
NOTE: Install branch circuit disconnect of adequate size per
NEC to handle unit starting current. Locate disconnect within
sight from and readily accessible from unit, per Section 440--14
of NEC.
Route Ground and Power Wir
Remove access panel to gain access to unit wiring. Extend wires
from disconnect through power wiring hole provided and into
unit control box.
Check
!
WARNING
es
DISCONNECT
PER N.E.C. AND/OR
LOCAL CODES
FIELD POWER
WIRING
3 PHASE ONLY
FIELD GROUND
WIRING
F i g . 8 --- Line Connections
F i g . 9 --- 3--Phase Monitor Control
(Applies to 3--Phase Units Only)
Table 3—3 ---Phase Monitor LED Indicators
LED STATUS
OFF
FLASHING Reversed phase
ON Normal
BLUE
GROUND
LUG
Nocallforcompressoroperation
CONTACTOR
24ABA24ABR
A94025
A00010
7
!
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Ensure compressor rotation is correct.
S 3--phase scroll compressors are rotation
sensitive.
S A flash LED on phase monitor indicates
reverse rotation. (See Fig. 9 and Table 3)
This will not allow contractor to be energized.
S Disconnect power to unit and interchange 2
field--wiring leads on unit contactor.
Connect Control Wiring
Route 24--v control wires through control wiring grommet and
connect leads to control wiring. Refer to Installation Instructions
packaged with thermostat (See Fig. 10)
24ABR
Use No. 18 AWG color--coded, insulated (35_C minimum) wire.
If thermostat is located more than 100 ft. from unit, as measured
along the control voltage wires, use No. 16 AWG color--coded
wire to avoid excessive voltage drop.
All wiring must be NEC Class 1 and must be separated from
incoming power leads.
Use furnace transformer, fan coil transformer, or accessory
transformer for control power, 24v/40va minimum.
NOTE: Use of available 24v accessories may exceed the
minimum 40va power requirement. Determine total transformer
loading and increase the transformer capacity or split the load
with an accessory transformer as required.
Final Wiring
IMPORTANT: Check factory wiring and field wire connections
to ensure terminations are secured properly. Check wire routing
to ensure wires are not in contact with tubing, sheet metal, etc.
STEP 8 —CompressorCrankcaseHeater
When equipped with a crankcase heater, furnish power to heater a
minimum of 24 hr before starting unit. To furnish power to heater
only, set thermostat to OFF and close electrical disconnect to
outdoor unit.
A crankcase heater is required if refrigerant tubing is longer than
80 ft. Refer to the Application Guideline and Service Manual
Longline Section--Residential Split--System Air Conditioners and
Heat Pumps.
STEP 9 —Install Electrical Accessories
Refer to the individual instructions packaged with kits or
accessories when installing.
Check
STEP 10 —Start-- Up
!
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this caution may result in minor personal
injury, equipment damage or improper operation.
To prevent compressor damage or personal injury, observe the
following:
S Do not overcharge system with refrigerant.
S Do not operate unit in a vacuum or at negative pressure.
S Dome temperatures may be hot.
S In 3 phase applications, incorrect phasing will cause reverse
rotation, resulting in elevated noise levels, equalized
pressures and reduced current draw. Correct by reversing
power connection L1 and L2 on contactor.
!
PERSONAL INJURY HAZARD
Failure to follow this caution may result in personal injury.
Wear safety glasses, protective clothing, and gloves when
handling refrigerant and observe the following:
S Front seating service valves are equipped with Schrader
valves.
!
ENVIRONMENTAL HAZARD
Failure to follow this caution may result in environmental
damage.
Federal regulations require that you do not vent refrigerant to
the atmosphere. Recover during system repair or final unit
disposal.
Follow these steps to properly start up
1. After system is evacuated, fully open liquid and vapor
service valves.
2. Unit is shipped with valve stem(s) front seated (closed)
and caps installed. Replace stem caps after system is
opened to refrigerant flow. Replace caps finger--tight and
tighten with wrench an additional 1/12 turn.
3. Close electrical disconnects to energize system.
4. Set room thermostat at desired temperature. Be sure set
point is below indoor ambient temperature.
5. Set room thermostat to COOL and fan control to ON or
AUTO mode, as desired. Operate unit for 15 minutes.
Check system refrigerant charge.
Sequence of
Turn on power to indoor and outdoor units. Transformer is
energized.
On a call for cooling, thermostat makes circuits R--Y and R--G.
Circuit R --Y energizes contactor, starting outdoor fan motor and
compressor circuit. R--G energizes indoor unit blower relay,
starting indoor blower motor on high speed.
When thermostat is satisfied, its contacts open, de--energizing
contactor and blower relay. Compressor and motors stop.
If indoor unit is equipped with a time--delay relay circuit, the
indoor blower will run an additional 90 seconds to increase
system efficiency.
Operation
CAUTION
CAUTION
CAUTION
system:
8
A/C
THERMOSTAT
Typical
FURNACE
AIR
CONDITIO NER
A/C
THERMOSTAT
Typical
FAN COIL
AIR
CONDITIO NER
24 VAC HOT
24 VAC COM
COOL STAGE 1
INDOOR FAN
R
C
W/W1
Y/Y2
G
R
C
WHEAT STAGE 1
Y
G
C
24 VAC HOT
24 VAC COM
HEAT STAGE 1
COOL STAGE 1
INDOOR FAN
R
C
W/W1
Y/Y2
G
W2
R
C
C
G
A02326
24ABR
LEGEND
24--V FACTORY WIRING
24--V FIELD WIRING
FIELD SPLICE CONNECTION
C
CONTACTOR
A97368
F i g . 1 0 --- Generic Wiring Diagrams
(See Thermostat Installation Instructions for specific unit combinations)
9
STEP 11 —Check Charge
Factory charge and charging method are shown on unit
information plate. To check charge, follow the procedure below
and the subcooling temperature required as shown on charging
table on unit.
NOTE: If subcooling charging conditions are not favorable,
charge must be weighed in accordance with unit rating plate, ±0.6
oz/ft. of 3/8--in. liquid line above or below 15 ft., respectively.
Favorable conditions fall within the ranges given on the charging
chart on the outdoor unit plate.
NOTE: In longline applications, see Application Guideline for
special charging requirements.
EXAMPLE:
To calculate additional charge required for a 25--ft. line set:
25 ft. -- 15 ft. = 10 ft. X 0.6 oz/ft. = 6 oz. of additional charge.
Cooling Only Procedur
e
This system requires charging by the subcooling method.
24ABR
1. Operate unit a minimum of 10 minutes before checking
charge.
2. Measure liquid service valve pressure by attaching an
accurate gage to service port.
3. Measure liquid line temperature by attaching an accurate
thermistor type or electronic thermometer to liquid line
near outdoor coil.
4. Refer to unit rating plate for required subcooling
temperature.
5. Refer to Table 3. Find the point where required subcooling
temperature intersects measured liquid service valve
pressure.
6. To obtain required subcooling temperature at a specific
liquid line pressure, add refrigerant if liquid line
temperature is higher than indicated or reclaim refrigerant
if temperature is lower. Allow a tolerance of ±3_F.
STEP 12 —Final Checks
IMPORTANT: Before leaving job, be sure to do the following:
1. Ensure that all wiring is routed away from tubing and
sheet metal edges to prevent rub-- through or wire
pinching.
2. Ensure that all wiring and tubing is secure in unit before
adding panels and covers. Securely fasten all panels and
covers.
3. Tighten service valve stem caps to 1/12--turn past finger
tight.
4. Leave Owner’s Manual with owner. Explain system
operation and periodic maintenance requirements outlined
in manual.
5. Fill out Dealer Installation Checklist and place in
customer file.
Table 4—Required Subcooling Temperature (°F)
Liquid
Pressure
at Service
Valve
(PSIG) 5 10 15 20
134 71 66 61 56
141 74 69 64 59
148 77 72 67 62
156 80 75 70 65
163 83 78 73 68
171 86 81 76 71
179 89 84 79 74
187 92 87 82 77
196 95 90 85 80
205 98 93 88 83
214 101 96 91 86
223 104 99 94 89
233 107 102 97 92
243 110 105 100 95
253 113 108 103 98
264 116 111 106 101
274 119 114 109 104
285 122 117 112 107
297 125 120 115 110
309 128 123 118 113
321 131 126 121 116
331 134 129 124 119
346 137 132 127 122
359 140 135 130 125
Required Subcooling Temperature (°F)
CARE AND MAINTENANCE
For continuing high performance and to minimize possible
equipment failure, periodic maintenance must be performed on
this equipment.
Frequency of maintenance may vary depending upon geographic
areas, such as coastal applications. See Owner’s Manual for
information.
Copyright 2005 Carrier Corp. S 7310 W. Morris St. S Indianapolis, IN 46231
Manufacturer reserves the right to change, at any time, s pecifications and designs without notice and without obliga tions.
Printed in U.S.A.
10
edition date: 02 / 0 6
Catalog No: 24ABR--2SI
Replaces: 24ABR--1SI
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